Simplify collection of current maintainers
Simplify collection of current maintainers

Only iterate over the current maintainers of a feedstock listed on the
GitHub team when the team exists. Otherwise we know there are no
maintainers and this iteration is unneeded.

conda-forge/conda-smithy,ocefpaf/conda-smithy,ocefpaf/conda-smithy,conda-forge/conda-smithy